Transformer



Feb. 14, 1928.

S. E. JOHANNESEN TRANSFORMER Filed Sept. s. 1926 2 Sheets-Sheet 1Inventor: Svend BJohannesen,

His Attorney 2 Sheets-Sheet 2 TRANSFORMER Filed Sept. 8, 1926 S. E.JOHANNESEN Feb. 14, 1928 Inventor-z Sven'd EJohanne sen,

by f

H is Attorn ey.

Patented Feb. 14, 1928.

ITED STATES SVENI) E. JOI-IANNESEN, OF PITTSFIELD, MASSACHUSETTS,ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

Application filed September 8, 1926. Serial No. 134,275.

My invention relates to transformers. The general object of theinvention is to provide an improved magnetic core and windingarrangement for transformers wherein those parts which are subjected tolarge 'difierences of voltage are Well separated and insulated. Anotherobject of the invention is to provide such a transformer with animproved casing wherein the transformer may be surrounded by a suitabledielectric material, preferably in the form of an inert gas.

Other objects and advantages will appear from the following descriptiontaken in connection with the accompanying drawings in which Fig. 1 is asectional view on the line 11 of Fig. 2 of an encased transformerconstructed in accordance with the invention; Fig. 2 is a view on theline 2-2 of Fig. 1; and Fig. 3 is an explanatory diagram showing themagnetic core and winding arrangement. Like reference charactersindicate similar parts in the different figures'of the drawings.

The invention will be described as embodied in the transformer shown inFigs. 1 and 2 and which includes two magnetic cores 10 and 11. Each ofthe cores 10 and 11 is formed of two parallel stacks of rectangularlaminations clamped together by end plates 12 and bolts 13. The twostacks of laminations of each pair are separate slightly to provide aventilating space 1 1. The two cores 10 and 11 are separated by a hollowrectangular insulating member 15 to the opposite faces of which thecores are secured by bolts 16. The member 15, which supports andseparately insulates the cores may be formed of any suitable mouldedcompound.

The high voltage winding is formed in two sections, one sectioncomprising the coils 18 Wound on the core 10 and the other sectioncomprising similar coils 17 wound on the core 11. The coils 17 areconnected in series between the high voltage terminals 19 and 20 and thecoils 18- are connected in series between the high voltage terminals 21and 22 so that, by means of suitable outside connections, the twosections of the high voltage winding may be connected either in seriesas shown in Figs. 1 and 2, or in parallel, as desired- The four highvoltage terminals 19, 20, 21 and 22 are moulded into the insulatingmember 15 and may have integral flanges embedded in the insulatingmember to help prevent leakage past the terminals of gas or otherdielectricmaterial surroundmg the transformer. The low voltage windingcomprises a single set of coils 23, each of these coils extendingthrough the insulating member 15 and being wound on both cores l0 and11. These low voltage coils 23 are connected in series between the lowvoltage terminals 2 1 and 25 of the transformer. 55

Thus the low voltage winding and one section of the high voltage windingare wound on the core 10 and the low voltage winding winding are woundon the core 11.

A. conductive connection 26 from each core to an intermediate point,preferably at or near the center, of the section of the high voltagewinding which is wound thereon and the other section of the high voltageserves to establish the voltage of each of the cores. It will beapparent that if these connectlons 26 are at the exact centers of thesections of the high voltage winding and these winding sections areconnected in series, then the greatest difierencein voltage that canoccur between any point of either core and any point of the high voltagewinding cannot exceed one quarter of the voltage between the terminalsof this winding.

There will be a voltage difference, of course, 35

between the two cores equal to one half the voltage of the high voltagewinding but the cores are well insulated by the insulating member 15upon which they are mounted.

The two ends of the transformer are en- W insulating member 15 may besecured by integral flanges 28 projectin from the caps and sealed intocorrespon 'ng grooves in the insulating member. The insulating member 15and the two end caps 27 constitute a casing which encloses thetransformer and.

which may be filled with any suitable dielectric material, preferably aninert gas such as helium or nitrogen or a mixture of such gases. The gasmay be introduced into the casing through a valve plug 29 and may beunder heavy pressure, if desired, to increase 1ts d1electric strength.The dielectric matcrlal serves not only as insulation for the '24 andare similarly connected to the outer surfaces of the end caps and thusthe necessity of openings andbushingsfor the low voltage terminalsthrough the casing is avoided. Withthis arrangement, the voltages of thetwo end caps differ by that of the low voltage winding but these endcaps are effectively insulated by the insulating member 15 to which theyare secured.

The principles and advantages of the invention have been explained inconnection with an encased transformer having two cores and acorresponding number of sections of high voltage winding. It will beapparent, however, that the invention is not limited, to this number ofcores and winding sections and that other chan es may also be madewithin the scope-oft e invention as defined b the appended claims.

What claim as new and-desire to secure by Letters Patent of the UnitedStates mediate point of each of said winding sections and its respectivecore, said winding of said cores, each of said cores being sectionsbeing connected to form one winding of said transformer, and a secondwinding wound upon all of said cores. '2. A transformer comprising aplurality of separately insulated magnetic cores, a separate windingsection wound upon each connected to an intermediate point of itsreective winding section, said winding sections being connected to formone winding two magnetic cores mounted respectively upon the oppositefaces of said insulating member and insulated from each other thereby, awinding formed in two sections wound respectively on said two cores,each winding section being conductively connected to its core, and asecond winding extending through the opening in said insulating memberand wound upon both of said cores.

5. A transformer comprising an insulating member having an openingtherethrough, 7

two conductive caps secured to the opposite faces of said insulatingmember to form a caslng therewith to enclose the core and windingelements of said transformer, said transformer having a winding with itstwo terminals conductively connected to the inner surfaces of said twocaps respectively, and two external terminals connected respectively tothe outer surfaces of said two caps. 1 6. A transformer comprising aninsulating member having an opening therethrough, two conductive capssecured to the opposite faces of said insulating member to form a casingtherewith to enclose the core and winding elements of said transformer,a winding having its terminals extending through said insulating member,a second winding having its terminals connected respectively to theinner surfaces of said caps, and two external terminals connectedrespectively to the outer surfaces of said two caps. In witness'whereof,I have hereunto set myhand; this third (3rd) day of September, 1926.SVEND E. JOHANNESEN.

